1. Field of the Invention
This invention relates to the field of cargo moving apparatuses for trucks and trailers.
2. Description of the Prior Art
Numerous different configurations of loading and unloading apparatuses for vehicles have heretofore been developed. Indeed, many U.S. patents have been granted for such devices. For example, see Pat. Nos. 2,916,169 granted to DeWitt; 2,507,252 granted to Hoover; 1,945,532 granted to Lima; 2,912,129 granted to Varrone; 3,905,494 granted to Yatagai and Tamura; 3,998,343 granted to Fors; and 4,111,318 granted to Lutz. It is significant to note that none of the above mentioned patents suggests nor discloses applicant's device.
In spite of the numerous developments in this field, there still exists a need for a more widely acceptable conveyor system. It can be appreciated that when undertaking the task of modifying a truck or trailer with elaborate conveyor apparatus, the cost thereof can often times not be justified. This is particularly so when considering the versatility of the well known and industry-wide use of forklifts or front-end loaders, at least from the standpoint of efficiency and economy. However, certain disadvantages or problems prevail in the use of such forklifts. Indeed, since certain of these disadvantages were so well stated in the above mentioned Fors patent '343, the following will be quoted therefrom:
"A steadily increasing volume of cargo is transported by truck trailer and must be loaded into the trailer at origin, unloaded from the trailer at freight terminals, and then sometimes reloaded on a local delivery truck and subsequently unloaded at its final destination point. Where possible, cargo is placed on pallets which are carried by front-end loaders into and out of the truck trailers. While such loading is relatively fast, it possesses a notable risk factor for the operator and others who must operate the loader in narrow, often poorly lighted trailers in close proximity to heavy objects which can easily fall or tip within the trailer. When the cargo is of a type impossible to handle with the front-end loader or one which is not easily shipped on pallets, the cargo must be loaded on the trailer by hand labor. In any event, the cargo is always transferred from the loading dock to the trailer starting with the loading of the front end of the trailer and progressing rearwardly until the trailer has been filled to the doors at the rear cargo entrance, a distance of up to fifty feet. If loading by hand, a laborer must make many trips back and forth along the fifty foot trailer before it is filled to capacity. It has been estimated that six men can work for approximately six hours to completely load a fifty foot, over the road truck trailer, and such loading is very tedious for the cargo handlers and understandably expensive for the trucking companies. PA1 "Even if hand loading and unloading can be avoided and front-end loaders carry the cargo into and out of the trailer, a high element of risk is present when the 5000 pound front-end loader enters the truck van carrying an additional load of several thousand pounds. An operator may not know until it is too late whether the truck flooring will hold the combined weight of the front-end loader and cargo, and any tipping or overturning of the heavily loaded loader in the narrow confines of the often dark and crowded van interior can be extremely perilous. Often the driver of the front-end loader is assisted by a second worker who leaves the front-end loader to inspect the necessary clearances and light the way while directing the driver of the loader. Accidents in which the lead workman is pinned against cargo or the sidewalls or where cargo falls on him are not unusual, and accordingly it is desirable to be able to load such trailers without driving the front-end loader into the trailer. PA1 "When cargo is unloaded from the truck trailer at freight terminals or at the final destination points, the unloading of the trailer presents the same danger and difficulties as those described for loading. With large and heavy loads, many men or heavy equipment may be required to unload the trailer and many man hours consumed while the expensive truck trailer remains idle and unable to continue its delivery missions until a substantial part of the load has been removed. PA1 "It would be desirable to provide a truck trailer which can be easily loaded and unloaded without requiring a front-end loader to drive within the truck or that workmen repeatedly walk the length of the van to pick up and deposit their loads. Additionally, it would be desirable to reduce the number of man hours required to fully load and unload the van."
Since the expensive elaborate conveyor systems seemingly are not feasible, and the perilous nature of the forklift being what it is, one of the practices in the industry in solving this problem has been to provide typical non-driven roller conveyors that must be man handled and placed on the floor of the dock leading into the cargo body of the truck or trailer. Obviously, this requires extra time and man hours to constantly be moving the conveyor apparatus from place to place. In addition, since this type conveyor is not power driven, additional work must be performed by the workmen in moving the cargo along the conveyor. This, of course, consumes additional man hours and hastens fatiguing of the workmen. Therefore, it would be desirable to incorporate as a permanent fixture of the vehicle an inexpensive simply constructed yet efficient power driven conveyor system to assist in loading and unloading these trucks and trailers. The present invention provides such a solution to the above described problems by: (1) eliminating the perilous nature of the front-end loaders, (2) eliminating the unnecessary man hours in moving typical roller conveyor apparatus from place to place, (3) eliminating the work required to move the cargo along this latter type conveyor, and (4) alleviate the expense involved in incorporating a conveyor system as a permanent fixture with a truck body.